Will the 21-70 Battery (a.k.a. 21700) Replace 18650?

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KeepingItLight
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Will the 21-70 Battery (a.k.a. 21700) Replace 18650?

This is a tricky question.

Right now, the most common Li-ion rechargeable is the 18650. As soon as Tesla ramps up battery production for the Tesla Model 3, however, that will change. Tesla has announced that the Model 3 will use 21-70 (a.k.a 21700) batteries. They are 21mm in diameter and 70mm in length. The large number that Tesla will need means that the 21-70 format will immediately become the most common Li-ion battery.

Many members here speculate that 21-70 will become available, and perhaps common, in flashlight designs within a few years. Whether it will replace 18650 in the long run has yet to be seen.

For those who have seen CD, DVD, and even Blu-ray, fade in popularity, it is hard to predict that Li-ion formats will remain unchanged. The best we can do is try to look forward, say, five or more years, and make our best guess. 18650 is almost certain to be viable over that time range. Ten or twenty years downstream is anybody's guess.

If you want to look forward twenty years, your best bet, by far, is AA. That's a format that has been around for more than a century.

Is 21-70 the future? What do you think?

 

 

Edited by: KeepingItLight on 08/28/2016 - 01:41
Speed4goal
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I think it may happen at some point in the future. The batteries tesla will produce for a long time probably won’t leave teslas hands. Its if they start making a deal with tool manufactures etc. I don’t really see laptops or powerbaks go with a bigger battery. It will increase size and weight. If anything I see them going with flatter more compact batteries. There are already size 10440,14500,16, 17650 18350, 18500, 26350 26650 etc multiple sized lithium batteries currently and they still havnt overtaken the 18650. Its still king. It would take a mass market switch to them. Which they may or may not be able to handle the supply them. Tool packs, laptops, etc would all have to switch over to this new size. If that happens then ya probably will become the new standard but many years away.

Even regular DVDs are still quite popular. It maybe a decade or more before it could happen. Manufactures probably sign multi year contracts with like makita, ryobi. Laptop manufactures etc. I don’t see the 18650 battery going anywhere in the near future. Even garden ligjts sre going to the 18650. If anything it seems like production is increasing not decreasing. Let’s not forget the millions of vaping units that run off 18650s. Even if this new battery takes over. The 18650 will still be around just like the other sizes mentioned above. They make up a very small percentage probably single digits of lithium battery sales but still readily available

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I think the Panasonic 21700s will only available be in Tesla’s supply chain for some time. If other users of li-ion cells such as power tool battery packs start using them then we may see them enter the flashlight market.

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Let us agree, that there are rumours about TWO different to-be-standard sizes. The 20700 and 21700.
Unsure to me if this is caused by erroneous calculations, or there will come a divine battle to settle this once and for all.

someone wrote:
Did you miss the word Panasonic? Evil
Yes and no. Articles were written about Samsung and about Panasonic.
So I have done some digging of my own and found: NCR20700B
If this is a fake than it has cost him/her a few hours of solid work.
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Henk4U2 wrote:
Let us agree, that there are rumours about TWO different to-be-standard sizes. The 20700 and 21700.

<snip>

All of the later stories I have seen, such as this one at Fortune, say 21-70. Initially, I was reading 20700.

I know your Internet research capabilities are top notch. What is the tenor of the articles your are now seeing?

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The future of the 21700? I haven’t got a clue. But there was a recent industry conference on advanced batteries for the automotive industry.

A very interesting peek at what is going on:
https://www.advancedautobat.com/uploadedFiles/AAB/Content/Conferences/AA...

http://advancedautobat.com/US/

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KeepingItLight wrote:

Henk4U2 wrote:
Let us agree, that there are rumours about TWO different to-be-standard sizes. The 20700 and 21700.

<snip>


All of the later stories I have seen, such as this one at Fortune, say 21-70. Initially, I was reading 20700.


I know your Internet research capabilities are top notch. What is the tenor of the articles your are now seeing?

Top notch or bonkers? The jury is still out on that one. I seems that Tesla from 2013 on has hinted on the abandonment of the 18650 standard. And in 2014 more and more rumours indicated the introduction of a 20700. But Elon Musk apparently has done some last minute math and has announced that 21-70 would become the standard (not only introducing a new standard size, but also a new standard description). This was last july at the Tesla Gigafactory tour.
Which makes more sense of the 21700 Samsung is developing for E-bikes.

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Henk4U2 wrote:
KeepingItLight wrote:

Henk4U2 wrote:
Let us agree, that there are rumours about TWO different to-be-standard sizes. The 20700 and 21700.

<snip>


All of the later stories I have seen, such as this one at Fortune, say 21-70. Initially, I was reading 20700.


I know your Internet research capabilities are top notch. What is the tenor of the articles your are now seeing?

Top notch or bonkers? The jury is still out on that one. I seems that Tesla from 2013 on has hinted on the abandonment of the 18650 standard. And in 2014 more and more rumours indicated the introduction of a 20700. But Elon Musk apparently has done some last minute math and has announced that 21-70 would become the standard (not only introducing a new standard size, but also a new standard description). This was last july at the Tesla Gigafactory tour.
Which makes more sense of the 21700 Samsung is developing for E-bikes.

Any idea what they are trying to push 21700 to? 4000mah minimum I would think. Maybe up to 4500 with the right technology. Panasonic expected to have the 18650 4000mah released by now

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Thanks, Henk.

21-70 it is. With initial production due to begin by year's end, I doubt Tesla will back away from that size.

For carry in a pants pocket, 1x18650 is a tad larger than I typically prefer. Even the diameter of the ZebraLight SC62w is a tiny bit bigger than I like. In a coat pocket, of course, 1x18650 is fine.

In the hand, I think I would like 1x21-70 better than 1x18650. In a jacket pocket, the difference does not matter.

I say, bring on the 21-70. Even if it were to dominate the flashlight world, it should still be possible to get 18650 batteries for a long time to come. There should be no hurry, therefore, to sell the 18650 flashlights I currently own.

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OK, looks like the info is out and the batteries soon to follow. Great article titled “‘Quantum Leap’ in Battery Innovations Presented at Eurobike”, full link: http://www.bike-eu.com/home/nieuws/2016/9/quantum-leap-in-battery-innovations-presented-at-eurobike-10127504

And the article also discussed the new 20700 Panasonic cell.

Quote:
3Tron system

BMZ further claims that its new 3Tron system offering a lifespan twice to three times as long as standard batteries will ‘revolutionize e-bike batteries’. Europe’s biggest battery supplier says, “With 3Tron, BMZ is putting its trust in a completely new format: instead of a 18650 (18mm diameter and 65mm high) cell size, 3Tron will be produced as a size 21700 cell (21mm diameter and 70mm high). The increase in output would not be possible with the standard format. The 3Tron battery system, as the first 21700 format system worldwide, is setting the standard in this new class – because it is clear that other manufacturers will follow and produce 21700 format batteries as well: the development possibilities of the 18650 cell format are exhausted.”
50% increase in energy supply

The 3Tron system also comes with high quality materials as stronger conductors which are built into the 21700 cell while the proportion of active cell material has been significantly increased. “This allows a full 50% increase in energy supply. Thanks to low internal resistance, the output increases by 68%. And the 3Tron’s discharge current is actually four times higher than that of standard battery cells. The new 3Tron battery is not only stronger, longer-lasting and higher in endurance than a 18650 cell, it is also lighter due to the premium materials used – as if predestined for the e-bike field,” claims BMZ.

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I was reading the other day some where the highest a 18650 can go is 4200 from Panasonic at around $40 a piece used with nano technology to make the sheets thinner. But can’t take the stress of today’s 2+ amp charging. And kept within industry use. With the slow charge and high cost no real market niche for it until technology improves It needs a low charge rate. These new Tesla celks will be 4200mah but can do rapid charging. It seems technology wasn’t advancing fast or cheap enough for Tesla to make cars go further without recharging

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Panasonic is hold their cards close to the vest, but these guys published that in addition to a 68% output, a battery which is exhausted after 3 years will now last 12 years. Those are huge things. One has to assume that Tesla and Panasonic, with the resources they have working on this issue, have achieved something similar.

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Nope- the 18650 is too well entrenched, too widely-used, too highly-developed, and too well-loved to be knocked off the throne by a newcomer. Perhaps in 10 years that will be different but I think my prediction is safe for at least 5 years.

Phil

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I sure hope the 21700 (aka 21-70) becomes the next oversized battery to take the place of the 26650. It’s only 3mm larger in diameter and 5mm longer than the 18650, yet has a lot more potential for future development whereas the 18650 has already topped out, development wise.

Presently, many protected and hi-cap 18650’s are close to 70mm long and 19mm in diameter so we were headed in that direction anyway.

I’m hoping for a BLF-SE model using a slightly enlarged version of the Eagle Eye X6R as the general format, including the latest version of the BLF backlit tailcap as our next big group-buy!

Article: Huge leaps in e-bike battery capacity coming to e-bikes soon by Elliot Johnston Nov 4 2016.

http://ebiketips.co.uk/content/news/…bikes-soon-428

“New, larger 21700 cell e-bike batteries from Samsung and German battery supplier BMZ, and a 20700 cell from Panasonic have pushed the envelope for e-bike power standards forward.” “Energy density is higher for the new cells, meaning that 700Wh batteries are likely to be commonplace by 2018.” “A 21700 cell can have a capacity of 4.8Ah, as opposed to 3.5Ah for an 18650 cell. “ “The unit also comes with high quality materials including stronger conductors and a greater proportion of active cell material which allows for a claimed 50% increase in energy supply and a 68% increase in output.” “…the development possibilities of the 18650 cell format are exhausted.”

 Also, the newest LG HG6 (20-65) 3000mAh 3.7V 30A discharge current 20650 battery is being advertised for use in power tools.

Questions/Answers here: http://www.answersingenesis.org/home/area/qa.asp “So then, each of us will give an account of himself to God.” Romans 14:12

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If they want a bigger FF (and volume) vs the 18650, why not just use the already entrenched 26650? Stick a protection circuit on it and it’ll be a 26700.

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Nahhhhhhhhhh…the 18650 is here to stay. Sure, any battery size may exceed it in production numbers, BUT, they will never exceed the number of 18650 sized battery tubes and hands that contain them.

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No, the only thing even close the popularity of 18650 is the 26650.
Highly doubt people will want to go with a lower capacity battery than a 26650 anyway, and if they do then 18650 is perfect.

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Tesla will make batteries in house and use them for their EVs and Powerwalls. Basically a closed system, no one else is making for Tesla.
So unlikely to have an effect
If they sell bare cells or get others to make for them then possible, though it would be many years if ever for phaseout of 18650, they are used in millions of devices that would all need retooling, and without a reason for mass defection it won’t be done.

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Angler wrote:
Lightbringer wrote:
If they want a bigger FF (and volume) vs the 18650, why not just use the already entrenched 26650? Stick a protection circuit on it and it’ll be a 26700.

It is a balance point.
As sizes get bigger, the empty space between curves gets larger when you lay them out in a row.

I think this cell size is the best ratio between cell capacity and wasted space in the pack due to cylindrical shape.

There is an old problem that goes: does a glass filled with large marbles have more empty space than a glass filled with small marbles. The answer is no. The large marbles make larger empty spaces, but the smaller marbles make more empty spaces. The amount of empty space is equal. However cylinders are different than spheres.

With cylinders the wasted space only existing in 2 dimensions versus 3 dimensions with a sphere. There is a small difference between the empty space of small versus large cylinders when filling a space. Finding the balance point between minimal empty space and maximum per cell capacity yields the most efficient pack.

I think.

Not sure that’s true. I’d scribe a unit circle in a unit square (L = D = 1), and the box scales up and scales down equally. With twice the diameter, you’d have 4 unit-squares instead of 1, but the ratio of space-to-stuff should stay identical. A cylinder would just stretch that in a 3rd dimension.

Packed in a zigzag fashion, you’d only have something different for edge-cases around the periphery.

Anyway…

I think more important would be the rather fixed thickness of the walls of the cells (ie, an AAAA won’t have a foil-thin wall), there’d be more active material in the bigger cells. Ie, by analogy, a jumbo box of cereal would be much more “efficient” vs a trial-size, considering the cardboard of the box is the same thickness in each, so the cereal:cardboard ratio is much higher in the jumbo box. Pretty much, the same goes for any packing material.

Plus, fewer connections total for fewer-but-larger cells, fewer protection circuits, less overhead in tops (even flattop caps), and so on. Otherwise, a nest of 10440s would be most efficient. Big Smile

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Bort wrote:
If they sell bare cells or get others to make for them then possible, though it would be many years if ever for phaseout of 18650, they are used in millions of devices that would all need retooling, and without a reason for mass defection it won’t be done.

And things like laptops if anything would go to a thinner profile, else use prismatic cells in nice rectangular packages.

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Angler wrote:

It is a balance point.
As sizes get bigger, the empty space between curves gets larger when you lay them out in a row.

I think this cell size is the best ratio between cell capacity and wasted space in the pack due to cylindrical shape.

There is an old problem that goes: does a glass filled with large marbles have more empty space than a glass filled with small marbles. The answer is no. The large marbles make larger empty spaces, but the smaller marbles make more empty spaces. The amount of empty space is equal. However cylinders are different than spheres.

With cylinders the wasted space only existing in 2 dimensions versus 3 dimensions with a sphere. There is a small difference between the empty space of small versus large cylinders when filling a space. Finding the balance point between minimal empty space and maximum per cell capacity yields the most efficient pack.

I think.


Pretty sure that packing circles in a 2 dimensional space works in the exact same way.
The height of the cylinders is completely irrelevant.

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Enderman wrote:
Pretty sure that packing circles in a 2 dimensional space works in the exact same way. The height of the cylinders is completely irrelevant.

You are so right.
I was confused because I actually posted that from the 5th dimension. Tired

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Angler wrote:

You are so right.
I was confused because I actually posted that from the 5th dimension. Tired


Haha Smile I wish I was there too.

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Lightbringer wrote:
Bort wrote:
If they sell bare cells or get others to make for them then possible, though it would be many years if ever for phaseout of 18650, they are used in millions of devices that would all need retooling, and without a reason for mass defection it won’t be done.

And things like laptops if anything would go to a thinner profile, else use prismatic cells in nice rectangular packages.


Indeed, i actually suspect laptops will be phased out in favour of tablets before they go to a different form factor.

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Considering how much of the batteries we use (high discharge 18650s) are greatly driven by the power tool industry it probably depends if they want to make the jump. Or rather if battery manufactures try to get them to by offering high discharge cells in that size. Considering so many power tool companies seem to want to sell different sized battery packs, from tiny 1p setup packs to large 3p packs. Maybe they’ll keep the 18650s for smaller packs and use these for larger ones. I know I’ve seen at least one power tool pack with 26650s, I think they were probably the older sony ones if I recall. It’s not that hard for them to switch toolings since its just some plastic molds that they replace anyway with new models and styling so it depends on the battery companies to offer cells they can use and in turn they will bleed into our market.

I think Tesla has a pretty good chance of sticking with these cells for quite some time, they’ve done the math on all the volume and cooling issues and that would only change if a significant improvement was made. Look how long 18650s have been around, they’ve probably advanced far more then lithium based batteries will in the near future. We are running out of improvements with this chemistry it seems. But who knows maybe they’ll just switch to some other energy storage system.

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they already have.most newer laptops i get in for service have thin lipo packs built in.

Lightbringer wrote:
Bort wrote:
If they sell bare cells or get others to make for them then possible, though it would be many years if ever for phaseout of 18650, they are used in millions of devices that would all need retooling, and without a reason for mass defection it won’t be done.

And things like laptops if anything would go to a thinner profile, else use prismatic cells in nice rectangular packages.

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so has anyone seen anywhere to buy these 21700 cells yet?

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Bort wrote:
Lightbringer wrote:
Bort wrote:
If they sell bare cells or get others to make for them then possible, though it would be many years if ever for phaseout of 18650, they are used in millions of devices that would all need retooling, and without a reason for mass defection it won’t be done.

And things like laptops if anything would go to a thinner profile, else use prismatic cells in nice rectangular packages.


Indeed, i actually suspect laptops will be phased out in favour of tablets before they go to a different form factor.

Nah, “virtual keyboards” suck except for extremely limited use, especially when they take up half the screen. Real keyboards won’t be going away anytime soon.

Tablets are only really good for primate-type pointy-clicky stuff (poke, poke, drag, drag), not entering text for any prolonged period.

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snakebite wrote:
so has anyone seen anywhere to buy these 21700 cells yet?

I checked a month ago, not available anywhere…
Just decide on 18650 or 26650, no reason to go in between if there is no benefit of energy density.

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